Science and Technology Fund Performance Management - Science and Technology Fund |
May 31, 2026 |
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| Prospectus [Line Items] | |
| Bar Chart and Performance Table [Heading] | <span style="color:#000000;font-family:Arial;font-size:12pt;font-weight:bold;">Performance Information</span> |
| Performance Narrative [Text Block] | The below bar chart and table illustrate the risks of investing in the Fund by showing changes in the Fund’s performance from calendar year to calendar year and comparing the Fund’s average annual returns to those of the S&P 500® Index (a broad-based securities market index) and the S&P® North American Technology Sector Index, which is relevant to the Fund because it has characteristics similar to the Fund’s investment strategies.Fees and expenses incurred at the contract level are not reflected in the bar chart or table. If these amounts were reflected, returns would be less than those shown. Of course, past performance of the Fund is not necessarily an indication of how the Fund will perform in the future.Wellington Management Company LLP, which served as subadviser to the Fund since January 29, 2007, was terminated as a subadviser to the Fund effective September 30, 2024. Effective May 1, 2023, BlackRock Investment Management, LLC (“BlackRock”) was engaged as a subadviser to the Fund, replacing T. Rowe Price Associates, Inc., which had served as subadviser since the Fund’s inception. Effective July 22, 2022, Voya Investment Management Co. LLC (“Voya IM”) was engaged as a subadviser to the Fund, replacing Allianz Global Investors U.S. LLC, which had served as subadviser to the Fund since September 19, 2005. The percentage of the Fund’s assets that each subadviser manages may, at the adviser’s discretion, change from time to time. |
| Performance Past Does Not Indicate Future [Text] | <span style="font-family:Arial;font-size:10pt;">Of </span><span style="font-family:Arial;font-size:10pt;margin-left:0%;">course, past performance of the Fund is not necessarily </span><span style="font-family:Arial;font-size:10pt;">an indication of how the Fund will perform in the future.</span> |
| Performance Information Illustrates Variability of Returns [Text] | <span style="font-family:Arial;font-size:10pt;margin-left:0%;">The below bar chart and table illustrate the risks of investing in the Fund by showing changes in the Fund’s performance from calendar year to calendar year and comparing the Fund’s average annual returns to those of the S&P 500</span><span style="font-family:Arial;font-size:6.5pt;position:relative;top:-3.25pt;">®</span><span style="font-family:Arial;font-size:10pt;"> Index (a broad-based securities market </span><span style="font-family:Arial;font-size:10pt;margin-left:0%;">index) and the S&P</span><span style="font-family:Arial;font-size:6.5pt;position:relative;top:-3.25pt;">®</span><span style="font-family:Arial;font-size:10pt;"> North American Technology Sector </span><span style="font-family:Arial;font-size:10pt;margin-left:0%;">Index, which is relevant to the Fund because it has characteristics similar to the Fund’s investment strategies.</span> |
| Bar Chart Does Not Reflect Sales Loads [Text] | <span style="font-family:Arial;font-size:10pt;margin-left:0%;">Fees and expenses incurred at the contract level are not reflected in the bar chart or table. If these amounts were reflected, returns would be less than those shown. </span> |
| Bar Chart Closing [Text Block] | During the period shown in the bar chart:Highest Quarterly Return:June 30, 202034.34%Lowest Quarterly Return:June 30, 2022-24.02%Year to Date Most Recent Quarter:June 30, 202633.88% |
| Performance Table Heading | <span style="font-family:Arial;font-size:10pt;font-weight:bold;margin-left:0%;">Average Annual Total Returns</span><span style="font-family:Arial;font-size:10pt;"> (For the periods ended December 31, 2025)</span> |
| None | |
| Prospectus [Line Items] | |
| Year to Date Return, Label [Optional Text] | <span style="font-family:Arial;font-size:10pt;margin-left:0.0pt;">Year to Date Most </span><span style="font-family:Arial;font-size:10pt;margin-left:0.0pt;">Recent Quarter:</span> |
| Bar Chart, Year to Date Return | 33.88% |
| Bar Chart, Year to Date Return, Date | Jun. 30, 2026 |
| Highest Quarterly Return, Label [Optional Text] | <span style="font-family:Arial;font-size:10pt;margin-left:0.0pt;">Highest Quarterly </span><span style="font-family:Arial;font-size:10pt;margin-left:0.0pt;">Return:</span> |
| Highest Quarterly Return | 34.34% |
| Highest Quarterly Return, Date | Jun. 30, 2020 |
| Lowest Quarterly Return, Label [Optional Text] | <span style="font-family:Arial;font-size:10pt;margin-left:0.0pt;">Lowest Quarterly </span><span style="font-family:Arial;font-size:10pt;margin-left:0.0pt;">Return:</span> |
| Lowest Quarterly Return | (24.02%) |
| Lowest Quarterly Return, Date | Jun. 30, 2022 |